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Recovery Strategy for the Woodland Caribou, Southern Mountain population (Rangifer tarandus caribou) in Canada - 2014 [Final]

4. Threats

4.1 Threat Assessment

There is a variety of threats that directly and/or indirectly affect southern mountain caribou and their habitat. In this strategy, threats to southern mountain caribou were assessed using the International Union for the Conservation of Nature (IUCN) Threat Calculator. In the IUCN Threat Calculator, only the direct impacts of threats on population numbers are considered. Therefore, for threats that result in habitat alteration (such as industrial activities and fire) only direct impacts are considered in the ranking for those threats. For example, direct impacts from habitat alteration could include loss of forage leading to poorer caribou condition and reduced survival, or displacement to habitats where mortality due to avalanche is higher. The threat calculator only addresses new threats that will occur within southern mountain caribou ranges in the next 10 years.

The indirect impacts of habitat alteration leading to altered predator/prey dynamics and higher predation rates on caribou are considered only under predation (problematic native species). Aboriginal groups and others have frequently expressed to Environment Canada that two of the greatest threats to caribou recovery are habitat loss and predation.

Tables 5-7 summarize threats assessed for the Northern, Central and Southern Groups respectively, based on best available scientific information and some Aboriginal traditional knowledge. Many of the threats to southern mountain caribou and their habitat are related and may interact, in which case they can have cumulative impacts that may not be evident when threats are examined individually. The overall level of threat to southern mountain caribou, based on cumulative impacts of threats calculated by the IUCN Threat Calculator, is: High for the Northern Group, Very High for the Central Group, and Very High for the Southern Group.

Although the IUCN Threat Calculator only assesses direct impacts, the following sections of the recovery strategy include a discussion of both direct and indirect impacts of threats to provide a more complete understanding of the effects of each type of threat on southern mountain caribou.

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Table 5. Threats assessed for the Northern Group of southern mountain caribou using the IUCN Threats Calculator.
Cat.No.ThreatImpactTable 5 notetScopeTable 5 noteuSeverityTable 5 notevTimingTable 5 notewComments
1 Residential & commercial development1.1Housing & urban areasNegligibleNegligibleSlightHigh
  • Some impact of Houston on Telkwa and Anahim Lake on Itcha-Ilgachuz and Rainbow subpopulations
2 Agriculture & aquaculture2.1Annual & perennial non-timber cropsNegligibleNegligibleSlightHigh
  • Mostly hay
2 Agriculture & aquaculture2.3Livestock farming & ranchingUnknownSmallUnknownHigh
  • Guide-outfitter horses grazing in backcountry
  • Cattle grazing and feral horses in Itcha-Ilgachuz area
3 Energy production & mining3.1Oil & gas drillingLowSmallSlightHigh
  • Primarily in Graham annual range
3 Energy production & mining3.2Mining & quarryingLowSmallSlightHigh
  • Proposed mine(s) in Tweedsmuir annual range
  • Proposed mineral exploration in Graham annual range
  • Coal deposits in Telkwa annual range
  • Significant mineral exploration and a possible mine in Takla annual range
3 Energy production & mining3.3Renewable energyLowSmallModerate-SlightHigh
  • Windfarm potential in Graham annual range
4 Transportation & service corridors4.1Roads & railroadsMediumPervasiveModerateHigh
  • Expected expansion of roads due to logging and mountain pine beetle salvage logging, especially in Itcha-Ilgachuz, Tweedsmuir, Takla, Wolverine and Chase annual ranges, and potential increase in vehicle collisions
4 Transportation & service corridors4.2Utility & service linesNegligibleRestrictedNegligibleHigh
  • Proposed oil and gas pipelines in Graham, Chase, Wolverine, Takla and Telkwa annual ranges
  • Potential expansion of existing transmission lines
  • Potential development of new transmission lines to service new mining operations
5 Biological resource use5.1Hunting & collecting terrestrial animalsNegligiblePervasiveNegligibleHigh
  • No licensed hunting except for Itcha-Ilgachuz, Chase and Wolverine subpopulations where there is a 5 point bull restriction
  • Some First Nations harvest
  • Some poaching
5 Biological resource use5.3Logging & wood harvestingMedium-lowLargeModerate-slightHigh
  • Increased forest harvesting expected on most annual ranges for mountain pine beetle salvage
6 Human intrusions & disturbance6.1Recreational activitiesLowPervasiveSlightHigh
  • Includes snowmobiling, all-terrain vehicle (ATV) use, backcountry skiing, hiking
  • Snowmobiling is a concern for Itcha-Ilgachuz, Telkwa, Rainbow, Charlotte Alplands
  • Increased levels of use are expected with an increased level of access created by industrial development, particularly mountain pine beetle salvage harvesting
6 Human intrusions & disturbance6.3Work & other activitiesNegligiblePervasiveNegligibleHigh
  • Ground surveys (e.g., geology, forestry), aerial surveys, etc.
7 Natural system modifications7.1Fire & fire suppressionLowPervasiveSlightHigh
  • Fire is a natural disturbance on low elevation winter ranges
7 Natural system modifications7.2Dams and water management/useNegligibleSmallNegligibleHigh
  • Tweedsmuir caribou migrate across the Nechako Reservoir where log debris can be extensive along some shorelines
7 Natural system modifications7.3Other ecosystem modificationsLowPervasiveSlightHigh
  • Increased populations of moose and deer due to habitat alteration
  • Mountain pine beetle disturbance on most low elevation winter ranges and spruce bark beetle disturbance in some areas
  • High incidence of pine rusts on some low elevation winter ranges; treatment is to drag scarify, which affects terrestrial lichens
8 Invasive & other problematic species & genes8.1Invasive non-native/alien speciesUnknownUnknownUnknownUnknown
  • Potential for new animal diseases/parasites introduced from domestic animals, game farming or invading wildlife
  • Very little is known about this threat
8 Invasive & other problematic species & genes8.2Problematic native speciesHighPervasiveSeriousHigh
  • Primary predators include wolves, bears, wolverines, cougars
  • Increased predation expected due to: habitat alteration within and adjacent to annual ranges from industrial activities (forest harvesting, mining, windfarms, oil and gas) and infrastructure (pipelines, transmission lines) resulting in habitats favoured by other prey such as deer and moose, which in turn sustain higher numbers of predators; and facilitated access for predators into caribou annual ranges from expansion of roads and other linear infrastructure, and packed trails due to winter recreational activities
10 Geological events10.3Avalanches/landslidesLowRestrictedSlightHigh
  • Avalanches are a concern for Telkwa, Chase, Wolverine and Takla
11 Climate change & severe weather11.1Habitat shifting & alterationUnknownUnknownUnknownUnknown
  • Expected increase in elevation for treeline and changes to low elevation habitats but actual change in vegetation structure not expected in the next 10 years
11 Climate change & severe weather11.4Storms and floodingUnknownUnknownUnknownUnknown
  • Potential increased risk of thaw (or rain) then freezing events resulting in increased ice crusting and difficulty in accessing ground forage during winter
Table 6. Threats assessed for the Central Group of southern mountain caribou using the IUCN Threats Calculator.
Cat.No.ThreatImpactTable 5 notexScopeTable 5 noteySeverityTable 5 notezTimingTable 5 noteaaComments
1 Residential & commercial development1.3Tourism & recreation areasLowSmallSlightHigh
  • Potential expansion of existing ski hills
3 Energy production & mining3.1Oil & gas drillingLowPervasiveSlightHigh
  • Extensive in Quintette, Narraway, Redrock/Prairie Creek, A La Peche
3 Energy production & mining3.2Mining & quarryingMediumLargeModerateHigh
  • High coal potential; expected expansion of activities in Narraway, Quintette, Redrock/Prairie Creek, A La Peche, Burnt Pine
3 Energy production & mining3.3Renewable energyMedium-LowLargeModerate-SlightModerate
  • Windfarm potential on most annual ranges
4 Transportation & service corridors4.1Roads & railroadsLowPervasiveSlightHigh
  • Expected expansion of roads due to oil and gas, mining and logging, leading to a potential increase in vehicle collisions (vehicle collisions already a problem for A La Peche on Hwy 40)
4 Transportation & service corridors4.2Utility & service linesNegligibleRestrictedNegligibleHigh
  • Proposed oil and gas pipelines within and adjacent to most annual ranges
  • Potential expansion of existing transmission lines
  • Potential development of new transmission lines to service new mining operations
5 Biological resource use5.1Hunting & collecting terrestrial animalsNegligiblePervasive-LargeNegligibleHigh
  • No licensed hunting
  • Some First Nations harvest
  • Some poaching
5 Biological resource use5.3Logging & wood harvestingMedium-LowLargeModerate- SlightHigh
  • forest harvesting occurring within and adjacent to most annual ranges
  • expected increase in mountain pine beetle salvage on low elevation winter ranges
6 Human intrusions & disturbance6.1Recreational activitiesLowPervasiveSlightHigh
  • Includes snowmobiling, all-terrain vehicle (ATV) use, backcountry skiing, hiking, fixed-wing and helicopter access into backcountry
6 Human intrusions & disturbance6.3Work & other activitiesLowPervasiveSlightHigh
  • Ground surveys (e.g., geology, forestry), aerial surveys, etc.
7 Natural system modifications7.1Fire & fire suppressionNot calculatedSmallModerate-SlightLow
  • Fire is a natural disturbance on low elevation winter ranges
  • Lower risk in high elevation winter ranges where fire disturbance is infrequent
7 Natural system modifications7.2Dams and water management/useNegligibleSmallNegligibleHigh
  • Williston Reservoir bisects a large part of the Scott annual range
7 Natural system modifications7.3Other ecosystem modificationsLowPervasiveSlightHigh
  • Increased populations of moose and deer due to habitat alteration
  • Mountain pine beetle disturbance on most low elevation winter ranges
8 Invasive & other problematic species & genes8.1Invasive non-native/alien speciesUnknownUnknownUnknownModerate
  • Potential infection of chronic wasting disease introduced via game farming
8 Invasive & other problematic species & genes8.2Problematic native speciesVery HighPervasiveExtremeHigh
  • Primary predators include wolves, bears, wolverines
  • Increased predation expected due to: habitat alteration within and adjacent to annual ranges from industrial activities (oil and gas, forest harvesting, mining, windfarms) and infrastructure (pipelines, transmission lines) resulting in habitats favoured by other prey such as deer and moose, which in turn sustain higher numbers of predators; and facilitated access for predators into caribou annual ranges from expansion of roads and other linear infrastructure, and packed trails due to winter recreational activities
9 Pollution9.6Excess energyNegligiblePervasiveNegligibleHigh
  • Noise from gas plants, etc.especially in Narraway, Quintette, Redrock/Prairie Creek, A La Peche
10 Geological events10.3Avalanches/landslidesLowSmallSlightHigh
  • Avalanches have been responsible for about 6% of mortality in the Jasper subpopulations; the last 5 caribou in the Banff subpopulation were killed in a single avalanche
11 Climate change & severe weather11.1Habitat shifting & alterationNot calculatedUnknownUnknownLow
  • Expected increase in elevation for treeline and changes to low elevation habitats but actual change in vegetation structure not expected in the next 10 years

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Table 7. Threats assessed for the Southern Group of southern mountain caribou using the IUCN Threats Calculator
Cat.No.ThreatImpactTable 7 notebbScopeTable 7 noteccSeverityTable 7 noteddTimingTable 7 noteeeComments
2 Agriculture & aquaculture2.1Annual & perennial non-timber cropsNegligibleNegligibleSlightHigh 
2 Agriculture & aquaculture2.3Livestock farming & ranchingNegligibleSmallNegligibleHigh
  • Mostly due to horses; some cattle grazing
3 Energy production & mining3.1Oil & gas drillingNegligibleNegligibleUnknownModerate
  • Shale gas potential in the Kootenays in the long term
3 Energy production & mining3.2Mining & quarryingLowSmallModerateHigh
  • Mostly in the Barkerville, Kootenay and Kamloops areas
3 Energy production & mining3.3Renewable energyLowRestricted-SmallModerateModerate
  • Potential for independent power projects (e.g., run of the river) in the Columbia South and Columbia North annual ranges
  • Potential for wind-farms
4 Transportation & service corridors4.1Roads & railroadsMedium-LowPervasiveModerate-SlightHigh
  • Several subpopulations already cross busy roads (e.g., Highway 3, Mica Dam road)
  • Potential twinning of the Trans-Canada Highway
4 Transportation & service corridors4.2Utility & service linesLowSmallSlightHigh
  • Potential transmission lines for independent power projects
  • Potential twinning of the Kinder-Morgan oil pipeline
  • Proposed oil and gas pipelines in Hart Ranges annual range
  • Expansion of existing transmission lines
  • Potential development of new transmission lines to service new mining operations
5 Biological resource use5.1Hunting and collecting terrestrial animalsNegligiblePervasiveNegligibleHigh
  • No licensed hunting
  • Potentially some First Nations harvest
  • Some poaching
5 Biological resource use5.3Logging & wood harvestingMedium-LowLarge-RestrictedModerate-slightHigh
  • Most forest harvesting expected in valley bottoms but some high elevation habitat will also be affected, especially in the Barkerville, Columbia North, Columbia South, Frisby-Boulder and Central Rockies annual range
6 Human intrusions & disturbance6.1Recreational activitiesLowPervasiveSlightHigh
  • Includes snowmobiling, heli-skiing (including flight paths to and from ski areas), cat-assisted skiing, all-terrain vehicle (ATV) use, backcountry skiing, hiking
  • Primary concerns are snowmobiling and heli-skiing with some subpopulations exposed to both
6 Human intrusions & disturbance6.2War, civil unrest & military exercisesNegligibleNegligibleSerious-ModerateHigh
  • Mt Revelstoke/Glacier areas military run avalanche control
6 Human intrusions & disturbance6.3Work & other activitiesNegligibleLargeNegligibleHigh
  • Ground surveys (e.g., geology, forestry), aerial surveys, avalanche control, etc.
7 Natural system modifications7.1Fire & fire suppressionLowSmallModerate-slightHigh
  • Generally lower risk in high elevation winter ranges where fire disturbance is infrequent; however, several large fires have burned high elevation range in the southern area
7 Natural system modifications7.2Dams and water management/useNegligibleSmallNegligibleHigh
  • Existing reservoirs may reduce dispersal
7 Natural system modifications7.3Other ecosystem modificationsLowPervasiveSlightHigh
  • Increased populations of moose and deer due to habitat alteration
  • Some concern about mountain pine beetle and spruce bark beetle disturbance at low elevations
  • Subalpine fir beetle and 2-year cycle spruce budworm in Barkerville and Wells Gray
8 Invasive & other problematic species & genes8.2Problematic native speciesVery HighPervasiveExtremeHigh
  • Primary predators include wolves, bears, wolverines, cougars
  • Increased predation expected due to: habitat alteration within and adjacent to annual ranges from industrial activities (forest harvesting, mining) and infrastructure (pipelines, transmission lines) resulting in habitats favoured by other prey such as deer and moose, which in turn sustain higher numbers of predators; and facilitated access for predators into caribou annual ranges from expansion of roads and other linear infrastructure, and packed trails due to winter recreational activities
10 Geological events10.3Avalanches/landslidesMediumLargeModerateHigh
  • Avalanches have been responsible for up to 15% of mortalities in the Columbia North, Columbia South, Frisby-Boulder and Central Rockies
11 Climate change & severe weather11.1Habitat shifting & alterationUnknownPervasiveUnknownHigh
  • Expected increase in elevation for treeline and changes to low elevation habitats but actual change in vegetation structure not expected in the next 10 years

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4.2 Description of Threats

Threats are described below in descending order of direct impact to southern mountain caribou population trend (Tables 5-7).

4.2.1 Predation

(IUCN # 8.2 Problematic native species)

The most significant, immediate direct threat to all three Groups of southern mountain caribou is unsustainable predation. Increased predator abundance has resulted from habitat alteration due to industrial activities (Tables 5-7). Industrial activities such as forest harvesting, mining and mineral exploration and development, and oil and gas exploration and development remove or destroy southern mountain caribou habitat (mature and old forests) and create early seralFootnote 2 habitats favoured by other prey species such as moose and deer. Since wolf populations are sustained by moose and deer (Seip 1992b, Stotyn 2008, Williamson-Ehlers 2012), increased numbers of those prey species support higher numbers of wolves than would occur naturally in ecosystems dominated by older forests. Although southern mountain caribou may not be the main target prey species, they are taken opportunistically when encountered. In ranges with habitat alterations that provide favourable conditions for other prey species, predators such as wolves can increase in number, which can significantly reduce or even eliminate southern mountain caribou subpopulations (Seip 1991; Seip 1992; Wittmer et al. 2005b).

Predation risk is also affected by roads and linear features associated with industrial and recreational activities. In the Central Group, encounter rates between wolves and caribou increased with proximity to linear features (Whittington et al. 2011). In the Southern Group, wolf predation on caribou occurs in association with roads at the fine scale (Apps et al. 2013).

Wolves are the primary predator of southern mountain caribou (Edmonds 1988, Seip 1992b, McNay 2009, Whittington et al. 2011), but bears (Ursus sp.), cougars and wolverine (Gulo gulo) can be locally and/or seasonally important. Cougars and bears are a significant source of mortality for some subpopulations in the Southern Group (Kinley and Apps 2001, Wittmer et al. 2005b, Stotyn 2008) and bear and wolverine predation are important sources of mortality in some Northern Group subpopulations (Cichowski and MacLean 2005, McNay 2009).

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4.2.2 Industrial activities (habitat alteration)

(IUCN #3.1 Oil and gas drilling, 3.2 Mining and quarrying, 3.3 Renewable Energy, 5.3 Logging and Wood Harvesting)

Although the impacts of industrial activities do not generally result in direct mortality of southern mountain caribou, indirect impacts include facilitated movement of predators through caribou annual ranges and altered predator/prey dynamics due to habitat alteration, which lead to increased predation rates on caribou. Where infrastructure is involved (e.g., open pit mines, roads) or habitat is converted to other uses (e.g., agriculture), habitat alteration is essentially permanent. Fire-adapted forest habitat can take 60-80 years to recover following a harvest. More than 100 years may be required for high elevation subalpine habitat or low elevation cedar-hemlock forests to once again become suitable habitat for southern mountain caribou. For the Southern Group, forest harvesting not only converts old and mature forests in to young forests, but in many areas, low elevation cedar/hemlock stands are being converted to pine, spruce or Douglas fir (Psuedotsuga menziesii). Industrial activities can also affect caribou directly through impacts on forage lichens (Kranrod 1996, Sulyma 2001, Miège et al. 2001, Stevenson and Coxson 2007).

Habitat alteration resulting from industrial activities on southern mountain caribou annual ranges has been linked to: reduced spatial separation between caribou and other prey or predators (Peters 2010); reduced occupancy (Smith et al. 2000, Apps and McLellan 2006, Wittmer et al. 2007); reduced adult caribou survival (Smith 2004, Wittmer et al. 2007); and population declines (Wittmer et al. 2007).

The effects of habitat alteration due to industrial activities may reduce the viability of a southern mountain caribou subpopulation through increased predation rates within caribou annual ranges or displacement of caribou to areas of higher predation risk. This could lead to a reduction in the size of the annual range and potentially result in the extirpation of a subpopulation. In any given annual range, habitat alteration due to industrial activities reduces the suitability of adjacent habitat (Smith et al. 2000; Williamson-Ehlers 2012). In some cases southern mountain caribou may use areas of inadequate or degraded habitat (e.g., buffer habitat surrounding certain types of development), particularly in highly disturbed annual ranges where opportunities for movement to suitable undisturbed habitat are limited or unavailable (Williamson-Ehlers et al. 2013). In these situations southern mountain caribou are at a higher mortality risk. In addition, large-scale industrial disturbances to the landscape (e.g., widespread forest harvesting) can cause southern mountain caribou to discontinue their use of portions of the range (Smith et al. 2000).

Forest harvesting and mineral exploration and development are the primary industrial activities that affect southern mountain caribou. For the Northern Group and some subpopulations in the Central Group, salvage harvesting of mountain pine beetle-killed stands and mid-term timber supply issues are contributing to increased pressure to harvest within or directly adjacent to important caribou habitat. Coal exploration and development, oil and gas exploration and development, and wind-farms are primarily a threat to subpopulations in the Central Group, but wind-farms have also been proposed in subpopulation annual ranges in the Southern Group. In addition, independent power projects (IPPs) have been proposed in some areas in the Southern Group. These IPPs will affect low elevation spring and early winter ranges in cedar-hemlock forests.

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4.2.3 Roads and other linear features

(IUCN # 4.1 Roads and railroads, 4.2 Utility and service lines)

Roads impact caribou directly through vehicle collisions and increased access for regulated and unregulated hunting (Brown and Ross 1994). Mortality due to vehicle collisions has been an issue for the A La Peche subpopulation in the Central Group, and for the South Selkirk and Columbia North subpopulations in the Southern Group, but most southern mountain caribou subpopulations experience no or extremely low levels of this type of mortality.

Roads and linear features such as pipelines, seismic lines, and hydro transmission lines also affect southern mountain caribou indirectly through habitat fragmentation and potentially by improving the efficiency of movement for some predators. Linear features can also support permanent early seral habitat favoured by other prey species. For example, grass seeding on road and transmission line right-of-ways provides forage for other prey species. Southern mountain caribou avoid roads and other linear features (Oberg 2001, Hebblewhite et al. 2010a, DeCesare et al.2012, Williamson-Ehlers 2012) and avoidance extends well beyond the actual development footprint (Williamson-Ehlers et al. 2013).

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4.2.4 Recreational activities

(IUCN #6.1 Recreational activities)

Recreational activities that affect southern mountain caribou include: snowmobiling, heli-skiing, cat-assisted skiing, alpine/downhill skiing, backcountry skiing/snowshoeing, ATV use, hiking, hunting of southern mountain caribou (Itcha-Ilgachuz, Wolverine, Chase), and hunting of other species within southern mountain caribou annual ranges. Recreational activities can affect caribou through displacement (Wilson and Hamilton 2003, Powell 2004, Seip et al. 2007), increased levels of stress (Freeman 2008), creation of packed trails during winter that facilitate predator access to caribou habitat (Powell 2004), and increased vigilance and movement after human-caused sensory disturbance (Powell 2004). Displacement could force caribou into areas where mortality risk is higher. In the Southern Group, caribou were absent from an area that had extensive snowmobile use, even though the area contained high quality caribou habitat (Seip et al. 2007). Increased levels of stress hormones have been found in caribou up to 10 km away from winter recreational activities (Freeman 2008). Continued stress could lead to poor body condition and potentially lower survival and reproductive rates (Simpson and Terry 2000).

Environmental conditions can affect how caribou react to recreational activities. In Scandinavia, reindeer favoured areas of insect relief that were located far from human activity, but used insect relief areas where hiking levels were high if they did not have access to insect relief areas that were far from human activity (Skarin et al. 2004, Vistnes et al. 2008). In Newfoundland, during deep snow years, caribou responded more slowly and waited until snowmobiles were closer to them before fleeing than during lower snow years, presumably to conserve energy during years when it took more energy to move and food was less available (Mahoney et al. 2001).

Snowmobiling and heli-skiing are significant recreational activities that impact southern mountain caribou in the Southern Group. Snowmobiling is also a significant activity that impacts many subpopulations in the Central and Northern groups.

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4.2.5 Natural disturbances (habitat alteration)

(IUCN #7.1 Fire and fire suppression, 7.3 Other ecosystem modifications)

Fire and forest insects are the primary natural disturbance on low elevation winter ranges of southern mountain caribou in the Northern and Central groups. Fire can directly alter habitat through loss of mature conifer stands, lichens and other forage plants, and by creating barriers to movement. Indirectly, fire converts mature and old forests into early seral habitat favoured by moose and deer. Historically, when disturbance from a wildfire occurred, southern mountain caribou would shift their use of habitat from affected areas to areas that were more suitable. However, with the increase in industrial activities in most annual ranges there are fewer suitable areas available into which southern mountain caribou can move. When combined with human-caused habitat alteration, fire can threaten southern mountain caribou recovery even though it is a natural component of the forest ecosystem.

The recent mountain pine beetle (Dendroctonus ponderosae) epidemic has affected most low elevation winter ranges of southern mountain caribou in the Northern and Central groups. Mountain pine beetles attack mature pine stands, which are used by caribou during winter. Although initially dwarf shrub abundance increased and terrestrial lichen abundance declined following mountain pine beetle attack (Cichowski et al.2008, 2009, Seip and Jones 2010, Waterhouse 2011), abundance of dwarf shrubs has since declined and terrestrial lichen abundance has increased slightly (Cichowski and Haeussler 2013). Despite reduced terrestrial lichen abundance and a reduced canopy, southern mountain caribou continue to use beetle-killed stands to crater for terrestrial lichens (Cichowski 2010, Seip and Jones 2010). Continued research is needed to follow the ecosystem changes and caribou response to those changes as trees start to fall.

Pine rusts are also a concern on some low elevation winter ranges. The treatment for pine rusts is drag scarification (i.e. mechanical distruption of the forest floor), which impacts terrestrial lichens.

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4.2.6 Hunting

(IUCN #5.1 Hunting and collecting terrestrial animals)

Licenced hunting is closed for southern mountain caribou, with the exception of three Northern Group subpopulations (Chase, Wolverine, Itcha-Ilgachuz). Hunting for those subpopulations is regulated using hunting season length and a minimum 5-point bull size restriction. First Nations subsistence hunting occurs in some areas. The extent of unlicensed hunting is not known but suspected to be low for most subpopulations.

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4.2.7 Other Threats

Other threats that have a lower level of concern for all southern mountain caribou (although they may be of greater concern for individual subpopulations) include:

Climate change (IUCN # 11.1 Climate change – habitat shifting and alteration): The long-term effects of climate change and the implications on southern mountain caribou and their habitat are unknown. Greater weather variability and severe weather events are expected to increase with climate change and are likely to: increase the frequency and severity of wildfires and forest insect outbreaks; cause more freeze-thaw cycles, freezing rain, deep snow, and hot summer temperatures; and, result in changes to forest composition and food supply (Vors and Boyce 2009). Although climate change is not expected to result in major habitat shifts in the short term, climate-related changes in habitat are expected to favour deer and other prey species, thereby increasing predator populations and predation on southern mountain caribou, and facilitating the spread of diseases and parasites. Climate change may result in habitat change for southern mountain caribou, as it drives sub-boreal forests to shift northwards and subalpine forests to shift upslope, which could potentially negatively affect caribou in the long term. However, impacts of climate change on southern mountain caribou in the short term are expected to be low compared to other immediate threats faced by southern mountain caribou.

Avalanches (IUCN # 10.3 Avalanches/landslides): Avalanches are a known cause of southern mountain caribou mortality, especially in the Southern Group. In the Central Group, the last five caribou in the Banff subpopulation were killed in an avalanche in 2009 (Hebblewhite et al. 2010b), and an avalanche killed some caribou in the Brazeau subpopulation. In the Northern Group, at least three avalanche related mortalities have been noted for the Telkwa subpopulation (BC Ministry of Forests, Lands and Natural Resource Operations, unpublished data).

Parasites and Diseases (IUCN # 8.1 Invasive non-native/alien species): Viral, parasitic, and bacterial diseases can affect individual southern mountain caribou and may have effects at the subpopulation level, although it is not thought to be one of the major threats currently affecting southern mountain caribou.

Noise and Light Disturbance (IUCN # 9.6 Excess energy): Noise and light disturbance result in short-term behavioural and physiological responses of individual southern mountain caribou, including a startle response, elevated heart rate, and increased production of stress hormones. Sustained or repeated disturbance can result in avoidance of areas and the reduction in use of suitable habitat. Continued stress could lead to poor body condition and potentially lower survival and reproductive rates (Simpson and Terry 2000).

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